A man is determined to find justice after the loss of a loved one, even though he is incapable of fully remembering the crime, in this offbeat thriller. Leonard (Guy Pearce) is a man who is struggling to put his life back together after the brutal rape and murder of his wife. But Leonard's problems are different from those of most people in his situation; he was beaten severely by the same man who killed his wife. The most significant manifestation of Leonard's injuries is that his short-term memory has been destroyed; he is incapable of retaining any new information, and must resort to copious note-taking and Polaroid photographs in order to keep track of what happens to him over the course of a day (he's even tattooed himself with a few crucial bits of information he can't get along without). Leonard retains awareness that his wife was brutally murdered, however, and he's convinced that the culprit still walks the streets. Leonard is obsessed with the notion of taking revenge against the man who has ruined his life, and he sets out to find him, getting help from Natalie (Carrie-Anne Moss), who appears to be a sympathetic barmaid, and Teddy (Joe Pantoliano), who claims to be Leonard's friend, even though Leonard senses that he cannot be trusted.